System of transmitting images



Oct., i3, 1936.

J. w. MCKAY 2,056,974

SYSTEM OF TRANSMITTING IMAGES Filed Feb. 6, 1953 s sheetssheet 1ATTORNEY Oct. 13, 1936. J. w. MCKAY SYSTEM OF`TRANSMITTING IMAGES FiledFeb. 6, 1935 8 SheeltS-Sheet 2 lAyVENToR .fo/wv f1" KAY BY AMM Oct. 13,1936. J. w. MCKAY 2,056,974

SYSTEM 0F TRANSMITTING IMAGES Filed Feb. 5, 1933 8 Sheets-Sheet 5 Oct.1?, 1936. J. w. McKAY 2,056,974

SYSTEM OF TRANSMITTING IMAGES Filed Feb. 6, 1935 8 Sheets-Sheet 4 Jo/f/v144 N950/ ATTORNEY SYSTEM yOF TRANSMITTING IMAGES' Filed Feb. s, 1955 8sheets-sheet? ATTORNEY Patented O ct. 13, 1.936

SYSTEM F TRANSMITTING IMAGES John W. McKay, Brooklyn, N. Y., assigner toNational Television Corporation, Wilmington,

Del., a 'corporation of Delaware Application February 6, 1933, SerialNo. 655,350

'z claims.' (o1. 17a-s) This invention relates to a system oftransmitting images from one place to 'another by scanning an objecteld, transmitting the plu'- rality of light and dark elements thusobtained into a continuous series of impulses, and translating saidimpulses into light again and arranging them in an orderly manner toform the image.

In transmitting images by television at the 1o present time, an objectfleld is cut up into a plurality of lines, these lines being scannedsuccessively at the transmitting end and re-arranged again by a scanningdevice at the receiving end. There is no particular standard for thenumber lo of lines 'per picture for transmitting images. In

some cases as low as forty-ve lines per picturehave been used with goodresults while in other cases, especially where more detail is'desired,120 lines may be 4desirable or even as high as 180 lines per picture.

It is one of the objects of the present invention to provide atelevision system which is usable for transmitting images at differentnumbers of lines per picture.

Another object of the invention is to provide a television apparatuswhich may be changed to transmit or receive a diierent number of linesper picture while the machine is in operation.

Another object of the invention is to provide a television system inwhichl the number of lines per picture may be changed without changingthe size of the picture.

Other objects and objects relating particularly to the construction andassemblage of the various parts will be apparent as the descriptionproceeds.

Several embodiments of the invention have been illustrated in theaccompanying drawings in which:

Fig. 1 is a sectional plan view of a television receiving apparatus;

Fig. 2 is a sectional elevational view of the apparatus taken on theline 2-2 of Fig. 1;

Fig. 3 is a sectional elevational view of the scanning device used inthe apparatus of Fig. 1;

Fig. 4 is a fragmentary plan view of a clampi Fig. 7 is an elevationalview ot the upper and lower ends of the plate controlling sleeve,showing additional operating mechanism;

Figs. 8 and 9 are plan views of the two diier.- ent plates used in thedrum;

Fig. 10 is an elevational view of a modled 5 form of scanning drum;

Figs. 11 and 12 are plan views of the .two different plates used in thedrum of Fig. 10;

Fig.4 13 is an enlarged sectional side elevational view of the drumshown in Fig. 10; 10

Fig. 14 is an elevational View of the shaft and plate-supporting sleevewith the plates removed;

Fig. 15 is a sectional plan view taken on the line l5--l5 of Fig. 13;

Fig. 16 is a sectional elevational view of some l5 of the plates takenon the line lB--i of Fig. 15, and showing the plates set for receiving asixty line picture;

Fig. 17 is a sectional elevational view similar to Fig. 16 but showingthe plates set for receiv- 20 ing a line picture;

Fig. 18 is a sectional elevational view of a portion of the plates takenon the line I8-i8 of Fig. 15, and showing the plates set for a sixtyline picture; 25

Fig. 19. is a sectional elevation of the same plates showing them set`for a 120 line picture;

Fig. 20 is a sectional side elevational view of a different type ofscanning apparatus with means to change the number of lines per picture;30

Fig. 21 is a plan view of a portion of the changing mechanism of Fig. 20taken on the line zl-zl of Fig. 20;

Fig. 22 is a sectional elevational view of the plate controlling shaftof the apparatus shown 35 in Fig. 20;

Fig. 23 is a sectional plan view of the drum taken on the line 23'23 ofFig. 20;

Fig. 24 is a sectional plan view taken on the line 24--24 of Fig. 20 andshowing only the up- 40 permost plate below the section line;

Fig. 25 is a sectional plan view taken on the line 25-25 of Fig. 20;

Fig. 26 is a fragmentary elevational view of a portion of the shaftshowing the keyway for se- 45 curing the plates in one position;

Fig. 27 is a fragmentary elevational view of a portion of the shaftshowing the other keyway for securing the plates in their otherposition;

Fig. 28 is a sectional plan view showing the 50 means of shifting orchanging the distance of the light source from the drum to compensatefor the change in the number of lines per picture;

Fig. 29 is a fragmentary front elevational view of the invention appliedto a scanning discl and 55 showing the disc-adapted to be used with asixty line picture;

Fig. 30 is a fragmentary front view of the same scanning disc arrangedto scan a picture at the rate of one hundred and twenty lines perpicture;

Fig. 31 is a sectional side elevational view of the television apparatususing the scanning discs of Figs. 29 and 30;

Fig. 32 is a sectional front elevational view taken on the line 32-32 ofFig. 31; and

Fig. 33 is a sectional elevational view of a portion of the changeovermechanism taken on the line 33-33 of Fig. 3|.

Referring now more specifically to the drawings, the invention is shownin connection with a scanning apparatus as disclosed in the applicationof Arno Zillger, Ser. No. 626,579, led July 30th, 1932. In thisapplication the scanning apparatus comprises a drum formed of aplurality of plates, stacked one upon the other, and each having areflecting edge which is almost as long as the diameter of the drum.Each plate is turned slightly with respect to the plates adjacent to itso that the angles formed between ad.- jacent reflecting edges are equaland the edges themselves form a helix around the circumference of thedrum with the reflecting surface of the last plate on the bottom,forming the same angle with the top plate as exists between all of theother plates.

A linear source of modulated light varying in accordance with anincoming televisionsignal is positioned at the proper distance away fromthe drum so that only its reflection can be observed in the drum. Whenthe drum is rotated at a speed which synchronizes with the speed of thetransmitting scanning device, the reflecting surfaces will successivelycause the reflection of a small portion of the light source to flashacross the observers ileld of vision, and as these flashes of light aremodulated in accordance with the incoming signal the image will appearto the observer to be slightly behind the drum and is built up by thevisual memory of the observer who only sees one small point of light atany given instant.

In the application above referred to, the platesare all rigidly securedon a shaft, there being sixty plates, or one for each line of thepicture. With such a drum only sixty lines per picture can be scannedand if it is desired to transmit or receive a picture with a differentnumber of lines per picture the scanning device in question becomesuseless.4 The present invention provides means to shift the plates sothat they will assume a different angular relation with each other andhence a picture of a different number of lines may be received ortransmitted.

The construction of one apparatus for shifting these plates is best seenin Fig. 3. Here a motor I, adapted to run in synchrony with the motor ofthe transmitting station either by virtue of the same alternatingcurrent cycle in the power supply line of both or by some synchronizingapparatus (not shown) such as the toothed wheel well known in the art,is mounted ln a suitable cabinet 2, in a vertical position with theshaft 3 extending upwardly. in front of a window 4 provided in thecabinet for viewing the image. A short distance from the motor I, theshaft 3 is provided with a shoulder 5 upon which rests a sleeve 6 whichis rotatably mounted upon the shaft 3 and is approximately as long asthe number of reflecting plates are high. The shaft has a secondshoulder 'I a trifle above the top of the sleeve 6 and ashort portion 8of the shaft imf lying side by side and in the same plane.

mediately above the shoulder is threaded to receive the nut 9 which maybe tightened down against the shoulder and which therefore secures thesleeve 6 upon the shaft with a slight clearance to provide for rotationtherebetween.

' sion I5 which is slightly larger in diameter than the lower portion ofthe shaft 3 below the shoulder 5 and extends down almostto the motor andis provided for the purpose of controlling the rotation of the sleeve. Aflange I6 may extend outwardly from the upper edge of the skirt AI5 andis provided to support the stack of plates upon the sleeve. To this enda heavy plate I1 is positioned over the sleeve 6, having a hole in thecenter thereof sulllcient to fit over the skirt I5 so that the platewill rest upon vthe rim or flange I6. A plurality of plates I8 (seeFigs. 8 and 9) are stacked in a helix upon this supporting plate I'I,each being provided with a hole I9 in the center to receive the sleeve6..

The plates I8 may be rectangular in shape as illustrated in Fig. 8having the rectangular cut out portion 20 on each side of the center tolighten the weight thereof. In the present embodiment being describedone side or edge 2| only of the plate is'used in building up the imageand this edge is made highly reflecting, being preferably opticallyground and polished s o that it is perfectly straight with sharp edgesor corners to flt as closely as possible against the adjacent plate. Theedge 2| is preferably formed parallel with the axis of the shaft 3 butthis is not essential so long as all the reflecting edges of all theplates have the same angle with respect to the axis. The opposite edge22 of each plate and the ends 23 need not be provided with a reflectingsurface and are bevelled or ground down at a different angle to that ofthe reflecting surface 2| so that as the drum rotates no light will bereflected from the edge 22 or end edges 23 in the same direction as thelight from the reflecting edges 2|.

The plates as just described are stacked on the sleeve 6, the number ofplates used and the angle between them being determined by the number oflines per picture which it is desired to transmit or receive. Forpurposes of illustration I have arbitrarily chosen an apparatus for usewith either sixty lines or one hundred and twenty lines per picture. Toaccomplish this purpose I provide 120 plates which when arranged forsixty line transmission are stacked in pairs, each pair being turned atan angle of 6 with the pair immediately above or below it so that acomplete helix is formed from top to bottom of the drum and theuppermost pair of plates have an angle of 6\with the lowermost pair.Thus arranged each pair of plates forms one line of the sixty linepicture with the two edges 2| One plate of each pair is secured to thesleeve 6 while the other plate of each pair is secured to the shaft 3.When it is desired to change from a sixty line picture to a one hundredand twenty line picture I have only to rotate the shaft and sleeve withrespect to each other through an angle of 3, and every other plate inthe'stack will move through 3, and the result is that there will be onehundred and twenty plates positioned at 3 apart, forming a complete'helix from top to bottom with theupper plate spaced 3 from the lowerplate. When in this position the drum will scan lines per picture or foreach rotation of the drum.

One ofv each pair of plates is secured to the sleeve 6 and the other ofeach pair to the shaft in the following manner: The lowermost plate A ofeach pair is provided with a keyway 24 which is engaged by a key 25secured to the shaft 3 and passing through a slot 26 which is providedin the sleeve 6 (see Figs. 5, 8, and 9). I preferably provide the key 25parallel with the axis of the shaft and cut the keyways 24 in thealternate plates A at an angular distance of 6 apart so that when theplates are slipped onto the shaft they assume their proper position of 6apart. However, if desired, the key may be made spiral or helical andthe keyway 24 may be cut exactly the same for each plate. The slot 26 inthe sleeve 6 is exactly wide enough to permit the shaft 3 'toturn'through an angle of exactly 3 with respect to the shaft.

The uppermost plate B of each pair is provided with a keyway 27 intowhich is adapted to fit a key 28 which is rigidly attached to the sleeve6. The plate A is provided with a slot 29 which surrounds the key 28 andpermits movement of the sleeve with respect to that plate while theplate B is provided with a cutout slot 30 which is larger than the key25 and permits movement of the shaft without interference between thekey 25 and that plate.

It will thus be seen that all of the plates vA are attached to the shaft3 and will rotate with it through a limited angle depending on the sizeof the slot 26 in the sleeve v6, while all of the plates B are rigidlyattached to the sleeve 6 and will rotate with the sleeve. If the sleeveis then rotated in a counter clockwise direction with respect to theshaft 3 the plates will align themselves as is shown in Fig. 5 to give asixty line picture with each pair of plates in alignment. If the sleeveis, however, rotated in a clockwise direction with respect to the shaft,all of the plates B will turn in a clockwise direction a distance of 3so that the plates will then arrange themselves exactly3 apart for theone hundred twenty line picture.

It is desirable to secure the plates in position when they are either inthe one hundred and twenty or sixty line arrangement so that there canbe no slipping while the picture is being received, and it is alsonecessary to releasel this securing means when it is desired to shiftthe plates. It may also be desirable to shift the plates while themachine is in motion and an arrangement for accomplishing this purposehas been illustrated.

In order to secure the plates in position I prov vide a yoke or spider3l (Fig. 3) which is in the form of a rectangular plate slightly shorterthan the reiiecting plate and is provided at its ends with down turnedportions 32 adapted to bear upon the ends of the uppermost plate. These'f able hole 33? which is adapted to fit over the nut 9 (alreadydescribed) and may vhave vertical movement without binding on this nut.The sleeve I I already described is provided at its lower end with aflange 34 `which has an outer downwardly extending ring 35 adapted tobear upon 'the spider 3|, so that the sleeve II may be rotated in onedirection to cause it to thread downwardly on the threadedportion I0 ofthe shaft and thus press the spider downwardly'against the plates andpress the plates together. It will be noted that the spider engages theplates by the portion 32 at the ends of the platesso that the plates arenot forced ltogether at the center which might cause slight distortion.To`loosen the plates for changing their arrangement, the sleeve II isrotated in the opposite directiony which thereupon relieves the pressureon the spider 3l.

inner side of a sleeve 40. The lower bearingl ring 39a of the runway ismade removable to facilitate assembly of the spindle and rollers. Thesleeve 40 is movable in a cylinder 4I mounted on a bracket 42 which issecured to the cabinet 2 in any desired manner (not shown) The sleeve 40is provided with two or more outwardly extending pins 43 which passthrough helical slots 44 in the cylinder 4I so that rotation of thesleeve 40 will cause it to have limited vertical movement with respectto the cylinder. The spindle 36 also passes through a pair of slots 45ln the` sleeve II which are so curved that movement of the spindle 36up.or down will cause rotation of the sleeve II with respect to theshaft. This is clearly illustrated in Fig. 6. When the sleeve same timethe shaft and sleeve I I may be rapidly rotating with the rollers 38running in their runway 39 in the sleeve 40. The rotation of the sleeveI I asV has already been explained, will loosen or tighten the plates ofthe drum and by raising and lowering the sleeve 40 therefore the platesmay be loosened or tightened regardless of the speed of the machine.

In order to raise or lower the sleeve 40 I provide anotlierl sleeve 46which fits on the outside of the cylinder 4I and is rotatably positioned'there by means of a nut 41'.which may be screwed onto the threadedlowerend of the cylinder. The sleeve 46 may be provided with a pair ofvertical grooves 48, clearly shown in Fig. '1 as well as Fig. 3, soarranged that rotation of the sleeve 46 will cause the pins 43 which liein the groove 48, to be rotated, thus causing either upward or downwardmovement of the sleeve 40. dependingonv the direction of rotation of thesleeve. Clockwise rotation of the sleeve as viewed from above. willcause the pins 43 and the sleeve 40 to which they are attached to moveupwardly. while rotation in a counter clockwise direction will reversethe movement of the sleeve 40,

In order to rotate the sleeve 46 I provide at its upper end a ring ofbevelled gear teeth 49 which mesh with a bevel gear 50 mounted on ashaft 6I supported for rotation in bearingv members 52 forming part ofthe bracket 42 and passing .through a hole 53 in the cabinet wall whereit Y terminates in a knob 54 which may be manually rotated one way orthe other. From this description it is evident that rotation of the knob54 inv a clockwise direction will cause the sleeve46 to rotate in acounter clockwise direction and the sleeve 40 to move upwardly carryingwith it the spindle 36,*thereby causing the sleeve Il to loosen theplates on the drum. Rotation of the knob 54 in the other direction willcause the sleeve Il to tighten the plates on the drum, all this takingplace independently of the rotation of the drum so that it can be movingat full speed during this adjustment.

The method for rotating the sleeve 6 with respect to the shaft 3 may beworked out in a somewhat similar manner. To this end a spindle 55 ispositioned in a slot 56 (Fig. 6) inthe shaft 3 and extends throughoffset slots 51 in the skirt I5 whichis attached to the sleeve 6. Theslots in the skirt I are so arranged that movement of the spindle up ordown causes the 3 rotation between the shaft and sleeve.

In order to move the spindle up and down while the machine is inoperation, I provide a pair of rollers 56 rotatably mounted on the endsof the spindle 55 and adapted to roll in a runway 59 provided in asleeve 6l). The upper guide 6I of the runway 59 may be removably held inplace. if desired, by suitable screws 62 to permit the insertion of thespindle with its accompanying rollers. 'Ihe sleeve 60 may be mounted forlimited vertical movement in a cylinder 63 which is attached to themotor casing and is provided with a pair of helical slots 64 throughwhich extend a pair of pins 65'extending outwardly from the sleeve 66.The pins 65 also pass through a pair of vertical slots 66 in a sleeve 61rotatably mounted about the cylinder 63. 'I'his sleeve may be held inposition upon the cylinder by means of a nut 66 threaded onto the upperend of the cylinder while the lower end of the sleeve` rests upon aflange 69 forming part of the cylinder. The lower end of the sleeve 61is provided with a bevel gear 10 which meshes with a small bevel gear 1|mounted on ashaft 12 which is supported in bearing members 13 attachedto an arm 14 which forms an extension of the flange 69 on the cylinder63. through an opening 15 provided for that purpose in the wall of thecabinet 2 and terminates in a knob 16 which may be manually operated.Rotation of the knob will cause rotation of the sleeve 61 and consequentvertical movement of the sleeve 60, as the pins 65 run in the curvedgroove 64, which in turn causes the spindle 55 to move up or down,depending on the rotation of the knob, and the sleeve 6 to rotate withrespect to the shaft 3.

Let us assume that a sixty line picture is being y ,clockwise direction.'Ihis rotates the sleeve 46 in a counter clockwise direction, as viewedfrom above, and causes the pins 43 to move in the slot 44 so that theyare raised upwardly and thereby raise the sleeve 40, thus causing thespindle 36 The shaft 12 extends Y screwed, thereby releasing thepressure against the spider 3| and loosening the whole stack of plates.With the plates thus loosened the operator 4rotates the knob 16 in aclockwise direction. This turns the sleeve 61 also in a clockwisedirection and causes the pins 65 to move downwardly in the grooves 64resulting in the lowering. of the sleeve 60 which pulls downwardly withit the spindle 55. Downward movement of the spindle 55 causes the sleeve6 to rotate in a clockwise direction causing the upper plate B of eachpair of plates to move in a clockwise direction with respect to thelower plate A, and continual rotation of .the knob until it can beturned no farther will cause these plates to assume their properposition with the 3 angular Spacing.

When the plates have been properly positioned In a scanning drum of thisnature it is im' portant that the light be positioned a proper dis'-tance away from the drum. 'I'his distance depends on the angle betweenthe plates and the size of the drum. For a drum made up of sixtysurfaces spaced at 6 apart and being approximately 6" high with eachreflecting surface being about 7.2" wide, (the proportion for a standardmotion picture), the light is necessarily positioned about 48 inchesaway from the drum. With this positioning of the lig`ht the imagereceived will exactly fill the flat surface of the drum which appearswhen it is rotated. If the light is moved any nearer to the drum it willbe reflected from more than one surface at a time and hence as it ismoved toward the drum an- -other image will appear on the side of theilrst image, both images being narrower but having the same height.Further movement of the light towards the drum will cause additionalimages to appear until half a dozen or more are crowded onto the drum,the horizontal dimension of each image being shortened accordingly. Inlike manner if the light is moved away from the drum the image becomeswider and wider until only a portion of it can be seen on the drumwithout moving the eye from side to side. Because of this fact it isnecessary to change the effect of the distance of the light from thedrum when the plates are shifted from their sixty line position to their120 line position. y

The arrangement for carrying this into effect will be seen from aninspection of Figs. 1 and 2. In these ngures are shown `the preferredform of lamp for producing the line of light. This lamp may be similarin construction to that described and claimed in my prior illedapplication Ser. No. 628,321, filed August 11, 1932, and comprises arelatively small diameter tube 16 having an enlarged bulb 19 at one endand another bulb 80 at the other. The bulb 19 may contain the cathode ofthe lamp while the bulb 30 may contain the anode, and the tube and bulbsmay be provided with an ionizable gas under reduced pressure and maypreferably contain a metal vapor or u vapors, such as one or moreof vthevapors of mercury, caesium, sodium, or the like. When a current is runthrough this lamp and is modulated in accordance with an incomingtelevision signal, an intense bluish white light fills the tube 18 andilickers in accordance with the signal.

Fig. 1 shows the general layout of a television receiving systemembodying the invention, the apparatus being positioned in a cabinet 2provided with an opening 4 in the front for viewing the picture; Thecabinet. as shown, is approximately lsquare in cross-section and thedrum comprising the plates I8 mounted on the shaft 3 is positioned alittle in front of the center. A baille plate 8| is positioned so as toextend from the lefthand edge of the aperture 4 in a plane tangential tothe circumference of the drum, and around the` drum with a circularportion 82, and then in another plane 83 tangential to the drum,terminating on the righthand side of the opening 4. 4This bailleprevents any rays from the lamp reaching the drum from the wrongdirection and also prevents the observer from seeing parts of theapparatus through the drum as it rotates. The baffle is preferablycoated with a dull'black finish to prevent light reflection therefrom.The lamp 11 is -positioned on the other side of this baille to the leftof the drum, slightly to the rear thereof, and the light therefrom isarranged to be directed toward a mirror 84 at therear of the apparatuswhich redirects the light to another mirror 85 positioned in the rightforward cornerA of the cabinet. From the mirror 85 rays are vis thelamp.

directed through an opening 86 provided for that purpose in the baie83directly onto the rotating drum. If the drum is .rotating at theproper speed and the lamp is being modulated in accordance with anincoming signal, the sixty line picture appears a short distance behindthe drum to an observer standing in front of the cabinet.

'The lamp is provided with a cylindrical shield 81 having an open side88 through which the rays of light may pass to reach the mirror 84. Thisshield 8l may be mounted upon a gear wheel 89 which is rotatably mountedin a bracket plate 90 secured to the casing wall, and has a large enoughopening through its center to permit the enlarged bulb 80 of the lamp topass. The upper end of the cylindrical shield is rotatably positioned ina second bracket plate 9i so that by rotating the gear 89 thecylindrical shield 81 is rotated about The gear 89 meshes with a secondgear 92 rotatably mounted in the bracket plate 90 upon a shaft 93 to theupper end of which is attached a bevel gear 94.v The upper end of theshaft rotates in a bearing bracket 95 attached to the flange 69 which issecured to the motor casing. A secondshaft 96 is also rotatably mountedin this same bearing bracket 95 and has bevel gears 91 and 98 at itsends, the bevel gear 97 meshing with the gear v94 and the bevel gear 98meshing with the gear 10 on the sleeve 61.

Thus when the knob 'I6 is rotated in order to change the angle of theplates, the shield 81 is also rotated, thereby cutting off the lightwhere it normally passes to the mirror 84 and permitting it to pass inapproximately the opposite direction. A mirror 99 is positioned in theforward lefthand corner of the cabinet behind the shield 8| in such aposition as to receive the light from the lamp 11 and redirect it to amirror |00 positioned in the rear lefthand corner of the cabinet.

This mirror is so positioned that it again redirects the light toanother mirror II positioned just back of the drum and a little to theleft thereof' which in turn directs the light to the mirror 84 fromwhich it passes to the mirror 85 and to the Suitable bailles areprovided to cut o all stray rays of light and thus I provide a baille|02 which extends from about the center of the left-hand wall of thecabinet to the edge of the shield 81 and then rearwardly forming abaiile |03 extending to a point on the rear wall behind the mirror 84.The baille |02 has an opening |04 to permit the light to pass from themirror 99 to the mirror |00 while the baille |03 has an opening |05 topermit the light to pass from the mirror |00 to the mirror IOI. Anotherbale |06 may be provided froxn the edge of the drum rearwardly parallelto the rays passing'between the mirrors 84 and 85 and terminating at apoint just clearing the rays passing from the mirror IOI to the mirror84.

It will be evident from an inspection of Fig. 1 that when the shield isturned so that the open space 88 is forward of the light, the lightwill. travel approximately twice the distance that it does when the openspace is in the position shown. Hence the position shown will operatefor a sixty line picture while the rotation of the shield causes theadditional distance of light travel necessary for the one hundred andtwenty line picture. The shadow box in which the drum is positioned isalso provided with a lower baille |01 and an upper baille |08 so that inlooking into the cabinet nothing can be seen except the drum itself andthe reflection of the light therein.

In starting up a television receiving apparatus of this nature it isevident that the motormay not be in perfect synchrony with thetransmitting motor when it comes up to speed. This will result perhapsin seeing the bottom portion of one image and the top portion of anotherimage below it, or two side by side pictures may be seen with thedividing line'in the center of the drum. In some television receiversmeans are provided to rotate the entire motor so that a position may befound where theimage is per--r fectly centered with respect to thescanning device. Such an arrangement may be provided, if desired, in theapparatus comprising this invention, but I havefound a much simpler way.to eiect the framing of the image. I merely provide a brake which actsagainst the motor so as to slow it down slightly whereupon it will loseseveral rotations and when again it picks up speed it will be in theproper synchrony. To

this end the wheel i2 on the top of the motor The other end o f the rodis provided with a pushy button II3 which extends through an opening II4in the front wall of the cabinet. With the friction element IIO spacedslightly from the rim of the wheel I2, a ring |I5 attached to the. rodIII bears against the inner side of the bearing II2 and the rod is heldin this position by a spring II6 which bears against the ring II5 andagainst one. end of the inner bearing II2. The spring holds the rod inits outermostposition, and when it ispushed inwardly by the finger'acting against the push rod H3, the friction element pushes against therim |09 of the wheel lI2 and causes friction against the wheel vinaccordance with the amount of pressure exerted by the finger. Thefriction against the wheel I2 causesa. retardation of the motor shaftwhich can thus be caused to lose several rotay A tions so that the phasewill be changed when the motor again comes up to speed. By severalpushes on the push button ||3 it is possible to quickly synchronize themotor and frame the picture properly.

The foregoing description has been related to a scanning device havingrectangular plates, but it is possible to use the invention inconnection with plates having a different number of sides in which allthe sides are used for reflecting the light for the image. In theapplication of Arno Zillger, Ser. No. 633,388, filed Sept 16, 1932, ascanning device is shown an'd described in which triangular plates areused, each edge of which is made reflecting. Triangular plates are shownbecausethe triangular plates permit the longest reflecting surface for agiven drum diameter but other plates may be used with four or more sidesas desired.

Where the triangular plates are used and all of the edges arereflecting, it is necessary to only use one-third oi' the number ofplates which would be necessary if only one edge were made reflecting.Thus for sixty line pictures only twenty plates are necessary. Each ofthese plates is provided with one reflecting surface which is parallelwith the axis of the drum while another suri'ace is inclined toward thelower end of the drum and the third surface is inclined toward thc upperend of the drum. The inclined surfaces all bear the same angle withrespect to the axis of the drum.

Light reilectedlfrom the edges which are parallel to the axis of thedrum is directed outwardly in line with the reflecting edges. Lightdirected from the edges which are inclined toward the bottom of the drumis directed downwardly, while the light directed from the other `edgesis directed upwardly. For one-third of the rotation of the drum theupwardly inclined edges direct the light upwardly where a suitable prismor other optical system makes it visible to the observerin a positionabove the drum. A

second third of the rotation of the drum causes the straight surfaces toreflect the light into the eye of the observer who sees the imagecreated by this portion of the drum in its proper position upon thedrum. During the last third of the drum rotation the downwardly inclinededges reflect the light downwardly below the drum where it isintercepted by an optical system and redirected to the eye of theobserver. This builds up the image in three parts, one above, one evenwith, and one bellow the drum, while the three series of reflectingsurfaces pass the light source following the same horizontal path.

In carrying out this principle, the drum ||1 of Fig. 10 comprises aplurality of triangular plates ||8 mounted upon a shaft l| I3 forrotation by a motor |20. For a sixty line picture I provide forty platesarranged in pairs so that in eilect they act similarly to the twentyplates described in the above entitled application. Each of the platesis provided with a straight reflecting ysurface |21, and upwardlyinclined reflecting surface |22, and a. downwardly inclined reflectingsurface |23. Each of the reflecting surfaces has the same distance fromit to the center of the plate and hence when the plates are arranged inpairs the edges |2| of the two plates forming the the position indicatedin Figs. 16 and 17, which? ure, and the forty plates 'are then arrangedatv 3 intervals, each series forming one third of a helix around thedrum. The edges |22 and |23 will then assume a regular steppedappearance y as is indicated in Figs. 17 and 19.

In order to provide for the movement of alternate plates I provide aspool |24 which is mounted on the shaft I3 and rests upon a shoulder',|25 formed in the shaft. The spool is keyedto. the shaft by means of thekey |26. The spool comprises a central tubular member |21 which` fitsclosely upon the shaft, and an outer cylindrical member |28 which isspaced from the inner member by the webs |29.

Inasmuch as a slight error in the position of a keyway adjacent thecenter of one of the plates will throw the reflecting edges of theplates out considerably, I use the spool construction in order to placethe keyways as near the reflecting surfaces of the plates as possible.The spool |24, therefore, corresponds to the shaft of the oonstructionshown in the flrst few figures `and is provided with a key |30 whichextends outwardly a short distance therefrom and is parallel withrespect to the axis. A sleeve |3| is positioned around the cylindricalouter surface |28 of the spool and is provided with a slot |32 throughwhich the key |30 extends and which permits an angular displacement of 3between the spool and the sleeve |3|. The sleeve |3|-has a key |33extending outwardly therefrom and spaced in a counter clockwisedirection from the slot |32.

Each of the upper plates C of each pair of the plates is provided with akeyway |34 to ft snugly against the key |33, while a. slot |35visprovided spaced at 120 from the keyway |34 to receive the key |30,leaving spaceenough to permit angular movement of that key with respectto the plate of at least 3. In like manner the lower plates D are eachprovided with a keyway |36 to flt snugly over the key |30 attached tothe cylinder |28, and are also provided with a slot |31 spaced at 120 ina counter clockwise direc-v successive pair of plates must be cut at anangle of- 6 with respect to the plates immediately above or below them.vThe keyways in each plate of the stack therefore, will have a slightlydifferent position with respect to the keyways in any of the otherplates.

Due to the fact that the slots |36 and |31 are wider than the keys whichenter them, there willbe spaces in alternate plates all the way down thestack adjacent each of the keys where there is no metal. and hencethesetwo sides oi' the plates or of the whole assembled stack of plateswill be less in weight than the other side. Hence I prefer to provide aslot |33 in the plates C and a slot |39 in the plates D which is large'enough to compensate for this difference in Also, inasmuch asthe slot|32 extends completely down one side of the outer sleeve I3 I this sidewill be `less in weight than the opposite side. and I, therefore, preferto compensate for this diilerence by making the wall |40 of the cylinder|28 opposite the key |30 slightly thinner than the remainder of thecylinder so that there will be less weight on this side.

From the above description it is evident that by rotating the sleeve |3|with respect to the cylinder |28, one set of plates C will be moved withrespect to their next adjacent plates D so that all o f the plates maybe lined up at 3 spacing instead of the 6 for the pair, and the platesmay be thereby arranged for a one hundred and twenty line pictureinstead of a sixty line picture. In order to accomplish this movement ofthe sleeve with respect to the cylinder, I provide a ilange |4| on thelower end of the cylinder upon which the lower edge of the sleeve |3|rests, and on this flange I provide a pair of spaced apart lugs |42 and|43. These lugs extend upwardly a short dis-n tance beyond the bottomedge of the sleeve |3| but are spaced from the sleeve so as not tointerlere with its rotational movement. An adjusting spindle |44 mayhave one end smooth and mounted for rotational bearing in a suitablehole |45 providedv in the lug it-while the other end |41 of the spindlemay be threaded and may have threaded engagement with a tapped hole |49in the lug |43. At the center ol the spindle itt I provide a groovedenlargement |50 to receive a slotted linger extending downwardly fromthe sleeve lti. Rotation of the spindle |44, (which may be provided inthe end |61 with a slot |52 for turning it), will cause the finger I5|to move to the right or left as desired, thus rotating the sleeve |3i.

IThe sleeve iti may be provided with a lower flange |53 upon which theplates rest, and a washer i5@ may rest upon the topmost plate and beurged downwardly by a plate |55 held by a nut |55 threaded on the end ofthe shaft lit. The plate |55 and washer |56 hold these plates inposition and it is necessary to loosen the nut |56 before the plates maybe shifted and the number of lines per picture changed. In making thisadjustment, therefore, the operator will loosenthe nut |56 and then turnthe spindle itt with a screw driver until he gets the proper adjustment.When the plates have been properly positioned the nut |56 is screweddown again until the plates are rigidly secured.

In order to get the proper angular movement of the plates with respectto each other, I provide a pair or pins itl and |66 which are threadedrespectively into the upper ends of the lugs it and M33 and may be heldby lock nuts |59 and |60 respectively. When these pins |01 and |56 areproperly adjusted, the movement between the outer sleeve 53| and thecylinder |26 is limited to 3, and when the sleeve is in one extremeposition with respect to the cylinder, the plates are set for a one.hundred and twenty line picture, while when the sleeve is in theopposite extreme position the plates are set ior a sixty line picture.

In Fig. the general layout is indicated diagrammatically for producing apicture with this construction, although no attempt has been made toshow the accurate spacing of the various parts. A lamp I6I, similar tothat already described, is spaced from the drum I1 while an opticalsystem,

comprising the prisms |62 and |63 and a central.

plain glass portion |64 is positioned in the general plane of the drumand light but at a. different horizontal angle therewith so that theoptical system is not in the direct line between the light and the drum.As already described, rays from the lamp |6| strike the upwardlyinclined reflecting surfaces |22 so as to direct rays to the prism |62where they are'bent toward the eye and give that portion of the picturethe appearance of being above the drum. Rays from the straight side |2Iof the plates are sent back through the plain glass |64 and appear to beabout the same height as the drum, while rays from the downwardlyinclined surfaces |23 are reflected towards the prism |63 where they arebent toward the eye of the observer and give the appearance, for thisportion of the picture, of being below the drum. 'I'he general result isa complete picture which has the same width as the drum but is tallerthan the drum is high. All surfaces of the reflecting plates are usedand a smaller number of plates are necessary than with the apparatusiirst described, and hence the whole arrangement is lightened andcheaper.

While the scanningA apparatus of Figs. l0 to 19 has been described ashaving a changeover device which cannot be operated when the machine isin motion, it is obvious that the same arrangement as is used in theiirst modification shown in Figs. 1 to 9 inclusive might be used. It isalso obvious that some suitable arrangement similar to that used withthe first apparatus for changing the distance of the light is necessary.

While the forms of the apparatus shown in wherein it is possible tochange from any num` ber of lines to any other predetermined number oflines per picture, as for instance, from fortyiive lines to sixty linesper picture, is illustrated in Figs. 20 to 28. In these figures a drurn|65 is used which has a plurality of plates similar to those shown inFigs. l to 9, being rectangular in shape and having one edge reflectingwhile the other edges are bevelled so as to redirect light in adiii'erent direction from the reflecting edge.

in this arrangement the shaft itl of the motor |58 is hollow sothat aninner shaft |60 may be moved axially therewithin. The sleeve |61 has aiiange plate Il@ attached to it adjacent the motor upon which the plates|66 rest. The upper end I1I of the sleeve |61 is threaded to receive an-ut |12. which is in the form of a sleeve, and may be screwed down upona spider |13 which presses the plates against the lower plate |10 whenthe nut is screwed down into position. 'Ihe upper end of the sleeve |01extends somewhat above the drum and is provided with a cap |14 which isscrewed down t|e`ntly over the end nf the sleeve and has a hole |15through which the inner shaitg |69 may extend. The cap |14 rotates in abearing |16 provided in one arm |11 of a frame |18, the lower arm |10 ofwhich is attached to the motor |68.

'I'he inner shaft |69 is provided with two keyways |80 and |8| which arepositioned on opposite sides of the'shaft. Both keyways are verticali'or a distance on the shaft corresponding to fthe height of the stackof plates and then take the form of a helix curving to the right asAthey approach the upper end of the shaft. 'I'he key- Way 80 has itsvertical section arranged to receive snugly the inwardly extending keys|82 with which each plate is provided. The upper helical section |83 ofthe keyway y|80 is made considerably wider so that when the shaft isforced downwardly and the keys therefor move upwardly into the helicalportion |88', they are free to move with respect to each other withoutinterfering with the sides of the keyway. Each of the plates is alsoprovided with another inwardly extending key |84 opposite the key |82 tot into the keyway |8| on the opposite side of the shaft. The verticalsection of the keyway |8| is wide enough so that it clears the edges ofthe keys which are bevelled as indicated in Fig. 27, to

, snugly fit into the helical section |88 of the key- Way. When theshaft is in its uppermost position as indicated in Fig. 20, the platesare held securely by the keys |82 which lie snugly in the keyway I 80.When the shaft is moved downwardly, the keys |82 slip into the enlargedhelical section |83 of the keyway 80. Also. when the shaft is in itsuppermost position as indicated in Fig. 20, the keys |84 are looselypositioned in the vertical section of the keyway |8| and when the shaftis moved downwardly these keys flt into the helical section l|85 of thatkeyway where they are snugly held and accurately positioned.

If the plates are positioned for a sixty line picture with an angle of 6between every two plates with the shaft in its uppermost position, itwill be evident that as the shaft moves downwardly the angle between theplates is slightly increased,

and the pitch of the helices of the keyways is so determined that theangle increases from 6 to 8 which is the angle necessary for a picturehaving forty-flve lines. However, if Athe picture is to have forty-fivelines which is fifteen less than the number of lines used for a sixtyline picture, only forty-five of the plates beginning from the top willhave to be shifted in order to get the fortyflve line picture, and theremaining fifteen plates at the bottom may be left with the 6 spacingand will not be used when the picture is being received.

The sleeve 81 is provided with afpair of vertical slots |88 throughwhich the keys |82 and |84 in the plates may pass to enter the keywaysin the shaft, and these slots are widened into openings 81 where thekeys on the shifting plates necessarily move horizontally to change theangles of the plates. y

A mechanism is provided for loosening the nut |12 and shifting the angleof the plates while the apparatus is in motion, and this arrangement isworked out similarly to that described in the preceding pages inconnection with Figs. 1 to l0. The sleeve |81 is provided with a. pairof helical slots |88 on opposite sides thereof at a point Just above thestack of plates where it passes through the sleeve |12, which isprovided with a pair of vertical slots 88.

A sleeve |88 is mounted for vertical and rotational movement in acylinder |8| which is attached at its upper end by means of a flange 82to the frame |11. The sleeve has a lower inturned flange |83 whichsupports a bali race |84 for rotatably mounting a ring 88 withinl thesleeve |80. The upper side of the ball race is secured by an annularmember |88 held by an externally threaded ring |81. The ring |88 isprovided with a pair of oppositely and inwardly directed pins 88 Iwhich'extend through the slots |88 and |88 in the sleeves |12 and |81respectively, as is indicated, so that when thepins are moved verticallywith respect to the sleeve |81 they will cause a rotation of the nut |12with respect to the sleeve thereby screwing it down against the spider|18 or releasing it to loosen the plates.

On the outer surface of the cylinder |8|,'I provide another sleeve |89which is rotatably held between the flange |82 and the end of the sleeveby a ring 200 which is threaded onto the end of the cylinder. 'I'hesleeve |88 is provided with oppositely positioned Vertical slots 20|while the cylinder |8| has a'pair of helical slots 202. A pair of pins203 are mounted to extend outwardly from the sleeve |80. `These pinsengage the slots 202 and 20| in the cylinder land in the sleeve |88respectively. Rotation of the sleeve |88 causes the pins 208 to move inthe slot 202 in the cylinder |8| so that the sleeve |80 is movedupwardly or downwardly depending on the rotation of the sleeve |88.

y In order to rotate the sleeve |88, I provide a gear 284 at the upperend thereof which meshes with a bevel gear 205 mounted on the shaft 208.The shaft 208 is supported in a pair of bearings 201 and 208 which areformed as a part of the arm |11 of theframe |18, and the shaft extendsthrough a hole 208 through the front of the cabinet 2|0 and terminatesin a knob 2|| which may be manually rotated. Rotation of the knob 2| inone direction will cause the nut |12 to loosen while rotation in theother direction will cause the nut to tighten irrespective of the speedof the drum.

'In order to raise and lower the shaft, I provide at its upper end adisc 2|2 which may rotate in a ballrace 2 |3 supported in a. sleeve 2|4by means of a bottom flange 2|5 and a ring 2|8, threaded into theinterior of the sleeve. VerticaLmovement of the sleeve 2|4 will causethe shaft to move in the same direction. A cylinder 2|1 is secured bymeans of a lower flange 2 I8 to the arm 11 of the frame and extendsupwardly terminating above the top of the shaft. This sleeve is providedwith a pair of vertical slots 2|8 and has a suillcient diameter topermit the sleeve 2|4 to have both vertical and rotational movementtherewithin. A pair of pins 220 extend outwardly from the sleeve 2 4 andpass through the slots 2 8 in the cylinder 2|1 and into a pair ofhelical grooves 22| formed in Aan outer sleeve 222 mounted for rotationon the outside of the cylinder 2|1. The sleeve 222 rests upon the flange2|8 of the cylinder 2|1 and is held in position on the cylinder againstvertical movement by a ring nut 228 which is threaded onto the top ofthe cylinder. Rotation of the sleeve 222 causes the pins 220 to movevertically in the slots 2 I 8 of the cylinder 2 I1 Iand thereby causesthe shaft to move up and down.

The sleeve 222 is rotated by means of a helical gear 224 which isattached to the lower end thereof and a small bevel gear 228 whichmeshes with the gear 224 and is mounted upon a shaft 228. The shaft 228is 'mounted in a pair ofbearings 221 and 228 which form a part of thearm |11 of the frame |18 and extends through an opening 228 in the frontwall of the cabinet 2|0 where it terminates in a knob 280 for manualrotation. Rotation of the knob 280. as is evident, will cause a rotationof the sleeve 222 and a vertical movement of the inner sleeve 2|4 andconsequently vertical movement of the shaft.

Assuming that a sixty line picture is being ob- 75 tained by thisapparatus and it is desired to change to a forty-five line picture, theoperator will turn the knob 2| thereby loosening the plate and then turnthe knob 230 which forces the inner shaft downwardly and changes theangle of all the plates except the lower one, whereupon he will tightenthe knob 2|| again and the fortyfive line picture may be observed. y

As in the devices previously described, it is necessary to change thedistance of the light source from the drum and in this modification ofthe invention this is accomplished in a manner somewhat similar to thatdescribed for the preceding figures. Fig. 28 shows a sectional plan viewof the general arrangement Vwherein the cabinet 2|0 is provided with anopening 23| in the front thereof, and a shadow box 232 extendsrearwardly from the opening around the drum |65, being cut out at 233 onthe right side to permit the light from the mirror 234 to pass to thedrum. A pair of vertically spaced larms 235, integral with the frame|18, extend rearwardly to the rear wall 236 of the cabinet. The lamp 231has its upper bulb 238 above the upper arm 235 and its lower bulb 239below the lower arm, with the slender tubular part 240 of the lamppositioned in slots 24| provided for that purpose in the arms. Suitableplates 24|a may t into the slots 24| to reinforce the arms 235. A shield242 is positioned around the tubular portion 240 of the lamp and has a n243 extending outwardly from one edge and having sufficient height tofill wardly over the edge of the frame |18 and then forwardlyterminating at a point 249 adjacent the edge of the bevel gear 224 whichcontrols the up and down movement of the inner shaft. The bevel gear 224is provided with a lug 250 which extends outwardly therefrom and isadapted to strike the end 249 of the arm 244 to move it in one directionwhen the sleeve 2221s being rotated around the cylinder 2 Hand tostrikethe arm on the other side when the sleeve is rotated in the oppositedirection. This permits a movement of only a few degrees of the shield242 while the shaft operating sleeve 222 makes a complete rotation. Bythis means the arm 244 is caused to move through a, small angle when theangle of the plates on the drum is changed.

The space 25| between the plate 243 and the other edge of the shield 242forms a slot through which the light from the lamp throughout its lengthmay pass, and when the plates are arranged for a sixty line picture theshield is ypositioned as is indicated in Fig. 28 in which case the lightpassing through the slot 25| may be directed toward a mirror 252 fromwhich the light passes from the mirror 234 and to the drum in a manneralready described. When the number of lines is reduced to forty-five,the shield 242 will rotate slightly in a counter clockwise directionbringing the righthand edge of the slot 25| in such a position that therays of light are cut oif from the mirror 252. However, a closer mirror253 will receive the rays from the lamp and redirect them to the mirror234 thus cutting down the distance Vof the light from the drum. as isnecessary with` a reduction in the number of lines. The plate 243prevents any light from striking the mirror 253 when the shield is inposition for a sixty Aline picture.

In Figs. 29 to 33 inclusive, I have shown an arrangement whereby ascanning disc may be used with the invention as I do not Wish to belimited to any particular type of scanning apparatus. In thisarrangement I provide a scanning disc 254 rigidly attached to a flange255, by means of screws 256, the ange forming a part of a sleeve 251keyed to a motor shaft 258 which is rotated by the motor 259. In thisarrangement a glow lamp 260 is positioned behind the disc 254 and a lens26| is positioned in front of it so as to enlarge the image built up bythe disc as the size of such image is necessarily limited-by thecircumference of the disc. The lens 26| is mounted in the front of acabinet 262. The disc 254 comprises an opaque disc of metal or otheropaque materialand is provided with a plurality of holes 263 (Figs. 29and 30) arranged in a spiral around the circumference of the disc in amanner well known in the art, so that the outermost hole is spaced fromthe innermost hole a distance corresponding to the height of the pictureto be received, while the distance between every two holes is equal tothe width of the picture.

Such a disc rotating at the proper speed in front of the light 260 will`completely scan an area on the illuminated electrode of the lamp equalto thel size of the picture to be received, and as the light ismodulatingA in accordance with the incoming television signal thepicture appears on the edge of the disc. For a sixty line picture thereare necessarily sixty of the holes 263. If it is desired, however, tomake the apparatus changeable over to a one hundred and twenty linepicture, I provide a plurality of holes 264 positioned midway betweenthe holes 263 but having a diameter half the size of the diameter of theholes 263. If the holes 264 were the same size as the holes 263 and theone hundred twenty holes were permitted to scan the object field or thelight source, the lines of light formed would overlap due to the factthat the diameter of the holes 263 are just suiilcient to permiteach-hole to trace one line across the picture without overlapping.While the holes are shown somewhat exaggerated in the figure, it is wellknown in the art that this must be the relation between the diametersthereof and the spacing of the holes.

In front of the disc 254 and adapted "to rotate with it I position asecond disc 265 having a serrated spiral edge. The serrated edge of thedisc 265 is formed of a plurality of iingers 266 positioned in such awaythat they willnormally extend outwardly between the holes 263 so as notto interfere in any way with those holes but to cover the holes 264 asis clearly illustrated in Fig. 29. Each of the fingers 266 is, however,provided with a small hole 261 which is normally covered by the disc 254and hence serves no purpose when the disc 265 is positioned as it is inFig. 29 for the sixty line picture. However, when it is desired to shiftto the one hundred and twenty line picture, the disc 265 is rotatedslightly counter clockwise with respect to the disc 254 with the resultthat the fingers 266 each cover one of the holes 263 thereby exposingthe holes 264 as is clearly indicated in Fig. 30. That portion of eachof the fingers 266 which contains the hole 261 will then fall directlyover one of the holes 263, thereby cutting down the size of the hole 263to that of the holes 264, the holes261 in the fingers* 266 being exactlythe same size as the holes 264.

It will thus be seen that when the discs are in the position shown inFig. 29, sixty holes will ameter.

while the width of the one hundred and twenty ly moved between thediscand thel observer and line picture will be half that of the' sixty linepicture. This alteration in the proportion of the received image iscompensated for by a cylindrical lens (to be later described), which isautomaticaltends to widen the picture to its proper dimension. In Fig.31 is shown the mechanism for moving the disc 265 with respectto thedisc 264. To this end a sleeve 268 is rotatably mounted upon the 0sleeve 251 and'is provided with a flange 268 to which the disc 265 isattached. 'I'he sleeve 268 may be held against axial movement on thesleeve 251 by means of a washer 210 which in turn is held by a nut 21|vthreaded on the reduced end 5 212 of the sleeve. 'I'he sleeve 268 isprovided with a pair of grooves 218 which are curved so that one end isoffset from the other as shown in Fig.

f 33. The sleeve 251 is also provided with a pair of grooves 214 whichare parallel to the axis of -o rthe sleeve and align with one end of thegrooves 218 when the discs are in their sixty line picture position andwith the other end of the grooves 218 when the discs are in their onehundred and twenty line picture position. A pair of pins 215 l 5 extendthrough the grooves on each side of the shaft and are mounted in a ring216 which rotates in a ball race 211, mounted in a. sleeve 218 against aflange 218 on one side and secured by a ring 288 on the other, threadedinto the end i 40 of the sleeve.

The ring 216vwith its pins is free to rotate with the scanning element,but upon axial movement thereof, the pins slide in the grooves 218 and214 and cause the slight rotation of the disc 265 with 45 respect to thedisc 254 necessary to change from a sixty vline picture nto a onehundredvand twenty line picture.

Axial movement of the ring 216 and associated parts, is accomplishedbymoving the sleeve 218 50 axially. This is ldofne by mounting thesleeve 218 for axial movement in a tubular member 26| to which it iskeyed by the key 282 to prevent rotation therein. The sleeve is providedwith an end closure 288 in Vwhich is a tapped hole- 284 55 adapted toreceive the threaded end or a. shaft 285, the other end of which ismounted for rotation in a bearing 286- in the end 281 of the 'tubular'member 28|. This end 'is secured against the front wall of the-cabinetand the shaft ex- 60 tends through an opening 288 and is provided witha'knob 288 on the outside formanual manipulation. A pair of collars 280and 28| are provided attached to the shaft on the voutside and inside ofthe end wall 281 of the tubular member Ititil 28| so as to prevent axialmovement of the shaft 285.

"Rotation of the knob will 'cause the shaft to be threaded into or outof the end plate 288 of the sleeve 218 and thereby cause the sleeve to70 move backward and forward depending on which of the discs may thus belaccomplished independently of the rotation thereof.

In order to compensate for the diil'erence in width of the picture foraone hundred and twenty line picture as compared to a sixty line picture,I provide a cylindrical lens 282 which is mounted in a movable arm 288attached to a sleeve 284. The sleeve 284 fits around the tubular member28| and is held against a ribA 285 formed on the tubular member by aring nut 286 which is screwed.

onto the threaded end of the member. Thus mounted the arm 288 canoscillate about the tubular member, throwing the lens 282 into and outof position in front of the viewing lens 26|. To -oscillate the arm 298,I provide a small pinion 281 on the shaft 285 which meshes'with an idlergear 288 rotatably mounted on a lug 288 attached to the inside of thetubular `member 28| by means of a pin 808. 'I'he gear 288 has its upperedge extending through an opening 38| provided for that purpose in theupper edge of the tubular member 28|, andmeshes with rack teeth 802provided on the inner end of theV sleeve 284. The operator, therefore,has only to turn the knob 288 in order to shift both the lens and thediscs to change from a sixty line picture to a one hundred and twentyline picture, and this change may be made regardless of the speed of theapparatus.

While the lens 282 has been shown as a cylindrical lens adapted to alterthe image vertically and thus cut down its height, it is evident that aconcave cylindrical lens might be used to increase the width of theimage so as to make it the same size'for either picture.

From all the above description, it is evident that I have provided ascanning apparatus for television in which the number of lines perpicture may be altered and such alteration may be made while the machineis in motion so that it is possible to change from one system to anotherproviding the apparatus is designedfor those particular systems. Whilein all of the modifications two systems only are usable, it is evidentthat the apparatus may'be designed to accommodate more than two systemsby suitable changes in construction of the apparatus.

1 Where the number of pictures per second sent out by the transmittingstation is the same for systems of different numbers of lines perpicture the speed of the motor .will be the same. However, it is obviousthat if one system has a different number of pictures per second thespeed of the scanning element will have to be altered. This may be doneby using a motor having diil'erent synchronous speeds or by arrangingsuitable change speed gearing so vthat the speed of the scanning elementmay be set for the desired number of pictures per second.

All of the ilgures have been described in connection with receivingtelevision apparatus but it is obvious to those skilled in the art thatthe same devices are adaptable to transmitting television apparatus bythe vst .lbsi-,itution of a light sensitive cell for the modulated lightused or the substitution of a bright constant source of light for themodulated light while a bank of light sensitive cells is'positionedaround the subject whose picture is being transmitted. It is, therwfore, thought unnecessary to4 show a transmitting ing from the spirit ofthe invention, and -I do not, therefore, desire to limit myself to whathas been shown and described except as such limitations occurin theappended claims.

What I desire to secure by Letters Patent and claim is: l

l. A television apparatus comprising a scanning device, a plurality oflong thin reflecting elements on said scanning device arranged in planessubstantially parallel to the axis of said device and so positioned asto scan an image with a predeterminednumber of lines, means to alter theposition of'said elements so as to changev the number of lines which thedevice will scanon the image, a light source spaced from said scanningdevice a predetermined distance depending on the number of linesscanned, and means to simultaneously alter the effective position ofsaid light source when said element altering means is operated so as tocompensate for the alteration of the position of said elements andproduce an image of substantially the same size for either number oflines scanned.

2. A television apparatus comprising a motor, a shaft adapted to be'driven by said motor, a sleeve surrounding said shaft, a plurality ofplates mounted on said sleevein a stack, the plane of said plates beingperpendicular to the axis of said shaft, each of said plates having areecting edge and said reflecting edges being arranged in a spiral orhelix around the shaft so as to cause a complete scanning of an imagewith a predetermined number of lines for rotation of the shaft, means tokey alternate plates to said shaft, meansv to key the remaining platesto said sleeve, means to rotate said sleeve slightly with respect tosaid drum so as to cause a slight rotation of alternate plates withrespect to those adjacent to them whereby the number of lines perrotation of the shaft is altered, and means to compensate for thealteration of said reflecting surfaces so as not to substantially changethesize of the image produced.

3. A television apparatus comprising a shaft, a sleeve surrounding saidshaft, a motor associated with said sleeve and shaft to drive them,

a plurality of flat plates mounted on said sleeve in stacked relationwith the plane of the plates perpendicular to the axis of the shaft, areflecting edge on each of said plates, said reflecting edges beingpositioned in a helix around said shaft so that as the shaft rotates thereflecting surfaces will scan an image with a predetermined number oflines per rotation of said shaft, means to key said plates to saidshaft, and means to change the position of said shaft with respect tosaid sleeve whereby eachof said plates is rotated through a slight angiewith respect to the plates adjacent to it. f

4. A television apparatus comprising a sleeve, a shaft within saidsleeve, means to permit axial movement of said shaft within said sleevethrough a limited distance but to prevent rotational movementtherebetween, means to rotate said sleeve and shaft. a plurality ofplates mounted on said sleeve in stacked relation with the plane of saidplates perpendicular to the axis of said shaft and sleeve, a reectingsurface on each of said plates, such surfaces being arranged in a helixaround said sleeve so as to scan an image with a predetermined number oflines when said sleeve is rotated, a keyway on said shaft having astraight portion and a curved portion, the straight portion of saidkeyway having a length equal to the height of said stack of plates, akey on each plate adapted to fit in said keyway, and means to shift saidshaft within said sleeve so as to force said keys into the curved partof said keyway to thus change the angular relation between them.

5. A television apparatus comprising a plurality of stacked plates, eachplate having a reecting edge and said reflecting v,edges being arranged'so-.a to form a helix around said stack of plates, a'shaft passingthrough said stack of plates, a keyway in said shaft having a straightportion substantially equal to the height o'f said stack of plates and acurved portion, a key in each plate adapted to flt into said keyway tohold all of said plates in rigid position upon said shaft, meansoperable regardless of the rotation of said shaft to shift said shaftlongitudinally so as to force said keys into the curved portion of saidkeyway and change the angular relation of a portion of said plates.

6. A television apparatus comprising a stack of plates, a reflectingedge on each of said plates. said reflecting edges being arranged toform a helix around said stack of plates, a shaft extending down throughsaid plates, a keyway on said shaft having a straight portion andacurved portion, a key on each of said plates adapted to engage saidkeyway so as to hold said plates in fixed position, means operableregardless of the rotation of said shaft to move said shaftlongitudinally so as to force a portion of said keys into the curvedportion of said keyway and thereby cause a portion of said plates tochange their angular relation with each other,l and means to compensatefor the angular change between the plates so as to maintain the size ofthe build-up image.

`'1. A television apparatus comprising a piurality of stacked plates, areflecting edge on each of said plates, said reflecting edges beingarranged in the form of a helix around said stack of plates, a shaftextending through said stack of plates, a keyway on said shaft having astraight portion and a curved portion, a key on each of saidl platesadapted to ilt into said keyway so as to maintain said plates in fixedposition upon said shaft, means to move said shaft longitudinally withinsaid plates so as to force said keys into the curved portion of saidkeyway and thereby changing the angle of a portion of said plates withrespect to each other, a modulated light spaced from said plates, andoptical means to change the distance of said light from said plates whenthe angle of said plates is changed by shifting said shaft.

. JOHN W. McKAY.

